Internal-combustion engine



w. L wUEHR 2,393,084

INTERNAL-COMBUSTION ENGINE Filed Aug. 25, 1944 4 Sheets-Sheet l Jan. l5,1946.,

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Jan. l5, 1946. w. wuEHR 2,393,084

INTERNAL- COMBUSTION ENGINE Filed Aug. 25, 1944 `4 Sheets-Sheet 2 HHHJan. l5, 1946. w. L wuEHR v v INTERNAL-COMBUSTION ENGINE Filed Aug. 25,1944 4 sheets-sheet 3 Jan. 15, 1946 w. L. WUEHR 2,393,084

INTERNAL-COMBUSTION 'ENGINE Fuga Aug. 25. 1944 4 sneets-shet 4 sow . l fI' 30@ 2517 18g Patented Jan. 15, 1946 UNITED* STATES PATENT i oFI-icE ni l INTERNAL-erziz'torssrron ENGINE William L. Wnehr, Port Arthur, Tex.Application lumi z5, 1944. serial Nogssnors (ci. 12s-s1) Claims.

'I'his invention relates to internal combustion engines, and moreparticularly to compression ignition engines.

It is an object of the present invention to provide a compressionignition enginehaving an improved arrangement of cylinders, pistons andcrankshaft.

It is a further object of the present invention to provide an improvedcompression ignition engine in which the forces to be transferred to thecrankshaft -are distributed in a better manner than heretofore,v wherebythe stresses are reduced.

It is a further object of the present invention to provide a compressionignition engine which will be relatively iat and which will be suitablefor use as a power plant in airplanes, armored tanks, trucks, trains,boats, and. in multiple, for ship propulsion. y

It isa further object ofthe invention to provide an engine of thecharacter aforesaid having improved scavenging and fuel introduction.

It is a further object of the present invention to provide an improvedengine of the type aforesaid in which the necessary operations inconnec-k tion with the combustion of the fuel and the other stages ofthe cycle may be effectively carried out at high speed.

It is a further object of the present invention to provide an engine ofthe type aforesaid in which better control of the combustion is obtainedwith the air pressure capable of variation with changes of load. A

It is a further object of the present invention to provide an engine ofthe type aforesaid in which higher mean effective pressures areobtainable than have heretofore been commonly employed.

1t is a further object of the present invention to provide a compressionignition engine employing multiple cylinders with opposed pistonstherein constructed and arranged to provide high power output in arelatively restricted space.

It is a further object oi the present invention to provide a compressionignition engine in which access to the operating parts may be readilyhad for inspection, repair, and replacement.

It is a further object of the present invention to provide a compressionignition engine in/ which the various steps of the operating cycle areinterrelated in such manner as to provide eiiicient high speed operationwith low fuel consumption.

Other objects of the invention will be apparent from the annexedspecification and claims.

shown in Fig. 1;

Fig. 3 is a fragmentary vertical sectional view taken approximately onthe line 3 3 of Fig. l, but with the crankshaft moved back from theposition shown in Fig, 1;

Fig. 4 is a transverse vertical sectional view taken approximately onthe line 4 4 of Fig. l;

Fig. 5 is a transverse vertical sectional view taken approximately onthe line 5 5 of Fig. 1;

Fig. 6 is an enlarged horizontal sectional viewof one of the cylindersof the engine shown in Fig. 1;

Fig. 7 is a vertical'sectional view taken approximately on theline 1 1ofFig.6;

Fig.I 8 is a fragmentary vertical sectional view taken approximately ontheline 3 8 of Fig. 7;

Fig. 9 is a fragmentary vertical sectional view taken approximately onthe line 9 9 of Fig. 6;

Fig. 10 is a diagrammatic view showing the arrangement of the crankshaftand pistons in an engine in accordance with Fig. 1; I

Figli is a horizontal central sectional view showing a modified form ofan engine in accordance with the present invention; and

' Fig. V12 is s. diagrammatic view showing the arf rangement of thecrankshaft and pistons in an engine in accordance with Fig. 1l.

It-should, of course, be understood that the description and drawingsherein are illustrative merely, and that various modifications andchanges may be made in the structure disclosed without departing fromthe spirit of the invention. l

Referring more particularly to the Adrawings in the embodiment of theinvention illustrated in Figs. 1 to 10, inclusive, there is illustratedone formof enginevof the opposed piston type for two cycle operation.

The engine preferably includes a plurality of cylinders l5 arranged ashereinafter explained, and, as illustrated in the specific embodiment inFig. 1, a unit group of four cylinders I5 is provided. As indicatedfurther in Fig. 10 fourv of these unit groups are connected to acrankshaft The nature and characteristic features of the M it with thecrankpins Il and lin planes at 90 intervals, are preferably employed toprovide a more uniform torque. It will thus be seen that sixteencylinders are provided, and, as hereinafter explained, have thirty-twopistons connected to twelve crank pins.

For purposes of explanation the cylinders will be designated by lettersand as seen in Figs. 1 and 10, the cylinders A, B, C, D, E, F, G, H. I,J, K, L, M, N, O, and P are provided. The cylinders I of therespectively unit groups are (1) A, B, I

and J; (2) C, D, K and (3) E, F, M and N;

and (4) G, H, O and P.

'Ihe cylinders I5 are arranged in two rows, e. g. A to H, inclusive andI to P, inclusive, and the cylinders I5 in each row preferably havetheir longitudinal axes parallel and coplanar. The cylinders I5 aredisposed with the parallel axes in one row preferably offset with4respect to the parallel axes of the cylinders in the other row adistance suilicient to permit driving connection to the crankshaft I6 ashereinafter pointed out.

Each cylinder l5 is provided with a pair of` opposed pistons consistingof an inner piston I9 and an outer piston 28 movable towardsand awayfrom each other for compression and expansion. Each piston I9 and 20 atthe head end thereof is provided with a central dished portion 2l andwith a hollow semi-cylindrical port or passageway 22 in communicationwith the interior space or chamber 2 la provided by the dished heads 2iwhen the same are together at the central part of the cylinder I5.

A single crank shaft I6 is employed and is preferably provided with athree throw arrangement for each unit group of cylinders I5 and pistonsI9 and 20, with two crank pins I'I in alinement and one crank pin I8*spaced 180 from the pins I1 for purposes to be explained. The crank pinsI1 and I8 for the respective groups maybe suitably spaced at 90intervals as indicated in Fig. for equalization of the torque deliveredtoi the crank shaft. I5. The inner pistons I9 for the cylinders A and Iare connected to one crank pin I1 and the inner pistons I9 for the nextcylinders B and J are connected to another crank pin Il. The innerpistons I9 for the .cylinder A and for the cylinderv I opposite theretoare connected to the same crank pin I'I by separate connecting rods 25and the inner pistons I9 for theopposite cylinders B and J are connectedto the next crank pin I1 by separate connecting rods 25.

The outer pistons 20 for the cylinders A and I preferably are connectedthrough connecting rods 26 to slippers l21 .carried in guides 28. Therods 26 of adjacent pairs of pistons 20 are connected by cross arms 29from which side rods 38 are connected to cross head pins 3i carried incross head guides 32. The pins 3| are connected through connecting rods33 to the crank pin I8, the outer pistons 20 of a unit group ofcylinders thus being connected to one of the crank pins I8.

The manner of connection` of the pistons to the crankshaft and theinterrelationship of the piston action is illustrated diagrammaticallyin Fig. 10. The inner pistons I9 of cylinders A and B,andIandKareconnectedtocrankpins Il disposed in a plane arbitrarilyselected as a horizontal plane at a predetermined initial or zerolocation and the outer piston 20 of these samecylindersareconnectedtoacmnkpin I8 disposed in the same horizontal planebut 180 therefrom inthepathofthecrankpins. Theinnerpistons preferablyconnected to crankpins I1 disposed inthe same horizontal plane at the180 location with the outer pistons 20 of these same cylinders connectedto a. crankpin I8 inthe same horizontal plane but at the 0 location. Theinner pistons I9 of the cylinders E and F, and M and N, are preferablyconnected to crankpins i1 disposed in a vertical plane and below thehorizontal plane at a location which may be referred to as 90u while theouter pistons 20 of these same cylinders have their crankpins I1disposed in the same vertical plane but at a 270 location. The innerpistons I9 of the cylinders G' and H, and O and P, are preferablyconnected to crankpins Il disposed in a vertical plane at the 270location with the outer pistons 20 of these same cylinders having theircrankpins I8 disposed in the same vertical plane but at the 90 location.

It will be noted that in each instance the inner pistons I9 of each unitgroup and the outer pistons 20 of each unit group function in apredeter- ,i

mined relationship and further that a predetermined relationship existsamong the various groups. For example, when the pistons I9 and 20 in thecylinders A and B are in firing position, at the center of thesecylinders, the pistons I9 and 20 in the cylinders K and L aresimultaneously in ring position, and the pistons I9 and 20 in thecylinders I, J, C and .D are in exhaust and scavenging position.

The preferred firing order maybe set forth as ABKL, EFOP, CDIJ, GHMN,and then KLAB, OPEE, IJCD and MNGI-I, the four cylinders in eachinstance firing simultaneously.

At the center of each cylinder I5 a chamber 35 is provided whichsurrounds or encircles the cylinder I5 and is in communication with theinterior of the cylinder through the inlet ports 35. The chambers 35 areprovided with valves 38 which function as a combustion air inlet andscavenging air inlet valves, suitable mechanism being provided forcontrolling the opening of the valves 38 in the proper timedrelationship. Air supply chambers 39 are provided in communication withthe inlet sides of the valves 38 and air supply ducts 40 are provided incommunication with the chambers 39 for supplying air under pressure,preferably at about one and one-half atmospheres absolute, from anysuitable source (not shown). v

The inlet valves 38 for each cylinder I5 are preferably moved to closedposition by means of springs 4I and moved to open position by means ofrocker arms 42 which engage valve stems 43. The rocker arms 42 arecarried on suitable rocker shafts 44. The rocker arms 42 are actuated intimed relationship by air valve cams 45, each of which is provided witha. land 46 for moving the valves 38 to open position.

Cam shafts 48 and 49 are provided for each row of cylinders I5. The camshaft 48 is preferablyoperated from the crank shaft I6 through a geartrain which includes a driving gear 58 directly keyed to the crank shaftI5 and rotating therewith, a driven gear 5I carried by the cam shaft 48for driving the same and intermediate l I3 ofthe cylindersCandD.andKandLare 75 providedfordelivengfuelintimedrelationship o thecylinders I5.

`2.393,0 into the interior of the' oyunders ls and through yr the portor passageway 22 into the space 2I between the pistons I9 and 20. Thecam shafts 49 and 49. preferably carry suitably timed fuel de livery`cams 6I for actuating rocker arms 62 carried on suitable rocker shafts63. The vrocker arms 6 2 serve to actuate the fuel valves 60.

While any desired type of fuel valve 60 may be employed, capable ofdelivering the desired charge in the available time interval, a suitablefuel valve and operating mechanism therefor is shown in my copendingapplication for Letters Patentflled through apipe 10 at the other end ofeach cylinder I5. Y Q

The mode of operation of the engine illustrated in Figs. 1 to 10 willnow be pointed out. While 'any desired ring order may be employed thering order heretofore set forth is preferred. For purposes ofexplanation theaction within a single cylinder I willbe explained, `itbeing un` derstoodthat theoperationl of the other cylinders AI5 issimilar but in the proper timed relationship as herein indicated. Airfrom any suitable source of air under pressure, suchfor example asblowersv (not shown), is delivered through the ducts 40 to the airsupply passages 39at thek inlet-side of the air control valves 38. a a

Commenclng with the pistons I9 and 2n at the outer ends of their strokesand with the Vair inlet valves38 vopen,as the pistons I9 and 2|) moveinwardly the exhaust ports 65 at each end of the cylinders I5 are shutoil' bythe pistons I9 and 29. The cams I5 have theretofore opened Vtheair valves 33 so that air is introduced into the cylinder I5 through theinlet ports 36.l .The'iniet ports 36 are preferably arranged in suchmanner as to give the incoming air a rotary motion within the interiorof the cylinders I5; The cams 45 move to permit closing of the inletvalves 38 as the pistons I 9 and 20 continue their inward movement. Theair trapped in the cylinders I5 between the pistons I9 and 20 and in thechamber 35 is compressed by the further inward movement of the pistonsI9 and 219. As the pistons I9 and 20 approach each-other air underpressure is retained in the interior space 2 Ia and aportion of the airis forced into and retained in the chamber 35, the pistons I9 and 20 asthey approach the center of the cylinders I5 cutting off the inlet ports36. The air between the pistons I9 and 2D and in the space 2Ia at theiinal stage of compression is-ready to receive the fuel which isintroduced by and through the fuel inlet valves 69 in any desired mannerthrough the passageway 22, the fuel inlet valves 60 being timed in theiroperation by means of the cams 6I. The burning'of the fuel in the air inthe interior space 2 Ia provides a. force tending to separate thepistonsv I9 and 29. As the pistons I9 and 20 separate the air from thechamber 35 enters through the ports 36 with a rotary and turbulentmotion and aids in the combustion.

The expansionof the gases upon combustion provides the force for drivingthe pistons I9\and Fluid may be intro` e4 3 20 inthe usual manner. Asthefpistons I9 and 20 separate and approach the outer ends of theirstrokes, .the exhaust ports 65 are uncovered perthe movement of thepistons la and 2o the air. inlet valve '39 is also opened to' providescavenging of exhaust ports 66 while the pistons I9 and 29 are at theouter ends of their strokes.A The pistons the cylinders I5. The airforscavenging enters through thevalve 33,- the chamber v and the ports 36and drives the burned gases through the I9 and y2li then move inwardlyas before and the operation is repeated.

vThe pistons I9 and 29 in the various cylinsuitable intervalsfor-'torque transmission.' As inl dicated in Fig. l2 the crankplns arein'planes at vintervals to provide uniformtorque. In this form of theinvention sixteen cylinders'are provided and have thirty-two pistonsconnected to twenty-four crankpins.

The cylinders A to H, inclusive, are arranged in one row and thecylinders I to P, inclusive, in

another row with the cylinders in each row hav- Y ing their longitudinalaxes parallel andcoplanar.

Y The cylinders I5 are disposed with the parallel axes in one rowpreferably oifset with respect to the parallel axes of the cylinders I5in the other row a distance sufficient to permit driving connection tothe crankshaft. Y

Each cylinder I5 is provided with a pair of op- 40' posed pistons, as inthe other form of the in-V vention, consisting of an inner piston I9 andan outer piston. 20 movable toward and away from each other forcompression and expansion. The

pistons I9 and 20 -at the heads thereof are pref-l erably of thetypeheretofore pointed out, with central dished portions 2I and withsemi-cylindrical passageways 22 and a central space 2|a when together. o

A single crankshaft I6a is employed and is preferably provided with a`three throw arrange ment for each unit group 'of cylinders I5 andpissuitable guides 28a. The inner ends of the side rods' 30a areconnected Inside-connecting rods'` 33 by means of side rod crosshead,pins 3l, the ends oi' the side connecting rods 33' being rcarried insuitable guides 32. The side connectingv rods 33 for the outer pistonsZllare connectedrespectively to the'crankpins Illa. It will thus benoted'that the outer pistons 2li are connected for the cylinders A and Iareco'nnectedrto a` crankpin I'Ia disposed in ya planearbitrarilyselected as a .horizontal plane at a `zero location, and the outerpistons 2l!v of these cylindersare.

suitable source of air under pressure such, for example, as blowers (notshown) is delivered to the air supply es I! at the inlet side of the air180 with respect to the crankpin Ila forthese cylinders or at a 270location.

The inner pistons il of the cylinders C and 'K are connected to acrankpin ila at a 225 location withy the outer pistons for thesecylinders connected to crankpins Ilo positioned 180 therefrom or at a 45location. I

'I'he inner pistons I! of the cylinders D and L are connected to acrankpin ilo at a 135 1ocation, with the outer pistons for thesecylinders connected to crankpins lla positioned 180 therefrom or at a315 location.

The inner pistons I! of the cylinders E and M are connected to acrankpin I 1a at a 315 location, with the outer pistons 20 for thesecylinders connected to crankpins Ila positioned 180 therefrom or at a135 location.

The inner pistons I8 of the cylinders F and N are connected to acrankpin Ha at a 45 location, with the outer pistons for these cylindersconnected to crankpins ila positioned 180 therefrom or at a 225location.

The inner pistons I! of the cylinders G and f O are connected to acrankpin Ha at a 270 location, with the outer pistons for thesecylinders connected to crankpins ita positioned 180 therefrom or at a 90location.

The inner pistons l! of the cylinders H and P are connected to acrankpin ila at a 180 location, with the outer pistons for thesecylinders connected to crankpins I 8a positionedv 180 therefrom or at alocation.

It will be noted that in each instance the inner pistons I! of each unitgroup and the outer pistons of each unit group function in apredetermined relationship and that a predetermined relationship existsamong the unit groups.. Fior example, when the pistons i9 and 20 in thecylinder A are in ilring position the pistons I9 and 20 in the cylinderP are in firing position and at the same time the pistons i9 and 20 inthe cylinders I and H are in exhaust and scavenging position.

The preferred rng order is AP, FK, BO, DM, HIl CN, GJ, and EL; and thenPA, KF, OB, MD,

. IH, NC, JG, and the two cylinders in each Fuel supply valves I0preferably of the time4 heretofore referred to arealsoprovlded.

The cylinders l5 are provided with the exhaust ports t5locatedattheouterendsofthepaths of the pistons and are in commimicationwith exhaast chambers It which surround or encircle eachcylinder.

'IhemodeofoperationoftheengineilhistratedinFigsl1and12issimilartothatoftheengine control valves 88. Y

withthepistons llandlatthe outer ends of their strokes, and with the airinlet valves 3l open, as the pistons I! and 2l moveinwardlytheexhaustportsiateachendofthe cylinder liareshutoifbythepistonsIlandl.

.The cams 45 have theretofore opened the air valves 88 so that air isintroduced into the cylinder il through the inlet ports 36a with arotary motion. The supply of air is shut oii and as the pistons l! and2l continue their inward movement the air trapped in the cylinder Ilbetween the pistons I9 and II and in the air chamber 35 is compressed bythe further inward movement of the pistons. As the pistons I9 and Ilapproach eachotherairisretainedintheinterior space lia and a portion ofthe air is forced into and retained in the chamber 35. The pistons I9and 2l, as they approach the center of the cylinder i5. cut ofi theinlet ports 36a. 'I'he air between the pistons I! andllandinthespace2Iaattheilnalstageof compression is ready to receive the fuel which isintroduced by and through the fuel inlet valve il in the mannerheretofore pointed out. The burningofthefuelintheairintheinteriorspaoeAlla provides a force tending to separate the pistons I9 and 20. Asthepistons i8 and 2l separate the air from the chamber 35 enters throughthe ports 86a with a rotaryl and turbulent motion and aids in thecombustion.

The expansion of the gases upon combustion provides the force fordriving the pistons I0 and 20 in the usual manner.` As-the pistons I9and 20 separate and approach the outer ends of their strokes the exhaustports are uncovered, permitting the discharge of the exhaust combustionproducts. As the exhaust ports S5 are opened by themovement of thepistons I9 and 20 the airinlet valve I8 is also opened to providescavenging of the cylinders I5 in the manner heretofore pointed out. Thepistons I 9 and 20 tnenmove inwardly as before, .and the operation isrepeated.

The pistons I9 and 20 in the respective cylinders A to H, inclusive,operate in predetermined `timed relationship as heretofore pointed out.

By mounting the cylinders in the manner illustrated and heretoforedescribed and by providing a timed relationship between the outerpistons 20 and the inner pistons i9 of the cylinders in each unit groupand among the unit groups. a compact. strong and effective arrangementis provided. It will be noted that the connecting rods andthe pistonrodsall are adapted totransmit forces in straight lines with a minimum ofbendingstresses and withreduoedlikelihoodofiniury or excessive stressestherein.

I claim:

l. A compression ignition engine comprising spaced rows of cylinders,the cylinders in each of said rows having their longitudinal axesdisposedinaplaneinnerandoutermstonsineach v of said cylinders, a crankshaft between the rows of cylinders having a plurality of crankpins,means for connecting the inner pistons for opposite cylinders to acrankpin. and means for connecting the outer pistons for said cylindersto another crankpin. said connecting means for the outer pistonsincluding connecting rods connectedtosaidothercrankpinsiderodmemberssaid connecting rods to said outer pistons. and spaced guides alongwhich said side illustratedinl'iitominclusive. Airi'romany 76rodmembexsareslidablymovable,

2. A compression ignition engine comprising spaced rows of cylinders,the cylinders in one row having ther'longitudinal axes offset withrespect to the cylinders of the other row, inner and outer pistons'ineach of said cylinders, a crankshaft between the rows of cylindershaving a plurality of crankpins, means forconnecting opposite pairs ofinner pistons of opposite cylinders to a. crankpin, and means forconnecting outer pistons of the same cylinders to another crankpin.

3. A compression ignition engine comprising spaced rows of parallelcylinders with their longitudinal axes disposed in a plane, theAcylinders in one row having their longitudinal axes oiiset with respectto the cylinders of the other row, inner and outer opposed pistons ineaich of said cylinders, a crankshaft between the rows of cylindershaving a plurality of crankpins, means for connecting opposite pairs ofinner pistons for opposite cylinders to a. crankpin. and means'forconnecting outer pistons for said cylinders to another crankpin.

4. A compression ignition engine comprising spaced rows of parallelcylinders with their longitudinal axes disposed in a. plane, thecylinders in one row having their longitudinal axes oiset with respectto the cylinders of Vthe other row,

crankshaft including rod members rigidly connected to said outer pistonsand connecting rods between said rod members and said crankshaft.

8. A compression ignition enginecomprising spaced rows of parallelcylinders, the cylinders in for connecting said outer pistons in pairs.to said I crankshaft and said inner pistons in pairs to saidcrankshaft.y

9. A compression ignition engine comprising I spaced rows of cylindershaving theirlongitudinal axes disposed in a plane, air and fuel inletmeans at the central portions of each of said' cylinders, inner andouter opposed pistons in eachof said-cylinders,` said cylinders eac'hhaving eir-` Y haust ports at the outer end portions of the stroke ofsaid pistons, a crankshaft between the rows of cylinders, and means forconnecting said outer pistons in pairs to saidv crankshaftand said innerpistons in pairs-to said crankshaft, the: means for connecting the outerpisv tons to the crankshaft including rod members opposed inner andouter pistons in each of said cylinders, a crankshaft having a pluralityof being respectively connected in pairs tocrankpins at predeterminedlocations and the pistons remote from said crankshaft for the samecylinders being connected in pairs to crankpins at differentpredetermined locations.

5. A compression ignition engine'comprlsing spaced rows of parallelcylinders with their longitudinal axes disposed in a plane. thecylinders in one row having their longitudinal-axes offset with respectto the cylinders of the other row, inner and outer opposed pistons ineach of said cylinders, a crankshaft between the rows of cylindershaving a plurality of crankpins, said cylinders comprising unit groupsof at least two cylinders with at least one cylinder of the group ineach row, and means for connecting the inner and outer pistons of a unitgroup respectively to crankpins located half a revolution apart.

6. In a compression ignition engine, spaced rows of cylinders with theirlongitudinal axes disposed in a plane, a. crankshaft' between the v rowsof cylinders and having a plurality of crankpins, two opposed pistons ineach of said cylinders, and means for connecting the pistons of' anopposed pair of said cylinders to said crankshaft, said means includingconnections from the outer pistons of said cylinders to at least one yerankpin and connections from the inner pistons to at least onedifferent crankpin, the connections from the outer pistons includingconnecting rods actuated by said first mentioned crank pin and slidablymovable rod members rigidly connected to said outer pistons andconnected to said means for connecting the outer pistons to the rigidlyconnected to said outer pistons,V guides in parallel relationship tosaid cylindersalong' which said rod members are slidable,.andjconnecting rods connecting said rod members to-said crankshaft.

10. A compression ignition enginev comprising-. spaced rows of cylindershaving their longitudinall axes disposed in a plane, air inlet means atthe central portions of each of said'cylinders. fuel inlet means at thecentral portionsof eachof said l cylinders, linner and outer .opposedApistons in tions of the stroke of said pistons, a. .crankshaft betweenthe rows of lcylinders, and means for connecting said outer pistons inpairs'to said crankshaft and said inner pistons in pairs to saidcrankshaft, the means for connecting the outer pistons to the crankshaftincluding rod members rigidly connected to said outer pistons and.

disposed in the plane of the cylinders, guides in parallel relationshipto the longitudinal'axesof said cylinders and along which said rodmembers are slidable, and connecting rods connecting said rod members tosaid crankshaft.

11. A compression ignition engine comprising spaced rows of parallelcylinders having` ktheir longitudinal axes disposed in a plane, thecylinders in one row having their longitudinal axes offset with respectto the' axes of the cylinders of the other row, air inlet means at thecentral portions of each of said cylinders, fuel inlet.'

means at the central portions of each of said cylinders, inner and outeropposed pistons in each of said cylinders, said cylinders each having`eX- haust ports spaced longitudinally from said air inlet means 'andsaid fuel inlet means at the U outer end 'portions of thestroke of saidpistons, a crankshaft between the rows of cylinders, and means forconnecting said outer pistons in pairs to said crankshaft and said innerpistons in pairs to said crankshaft.

12. In a compression ignition engine, the combination of a crankshafthaving at least three crankpins; spaced cylinders on opposite sides ofsaid crankshaft and disposed with their longitudinal axes coplanar andwith the axis of one cylinderotiaetwithrespecttotheaxisotannthercylindenairinletmeansatthecentmlportion ofeachot said cylinders, fuelinlet means atthc centralportionoteachotsaidcylinderaapairoiinnerandouteropposedpistonsineachof said cylinders, connecting meansfrom corresponding pistons of opposite cylinders to one ofsaidcrankpinsandconnectingmeansfrmnthe 13. Inacompressionignitionengine.thecom binationofacrankshaithavingatleastthree crankpins, spacedcylinders on opposite sides said crankshaft and disped with theirlungimdinal axes cilanarandwith theaxisofonecylinderomtwithrespecttotheaxisofanothercylindenairinletmeansatiiecmtralportion of each of said cylinders. fuel inlet meansatthecentralportionofeachofsaidcylindcrs,apairofinnerandouteropposedpistonsineach of said cylinders, connectingmeans from corresponding pistons of Opposite cylinders to one of saidcrilnkpil'is.4 and connecting means from theotherpistonsoi'thesamecylinderstotheothers of said 14. In a compressionignition engine, the combination of a crankshaft having at least threecrankpins, two of which are inalinement. spaced cylinders on oppositesides of said crankshaft and disposed with their longitudinal axescoplanar and with the axis of one cylinder offsetwithrespecttotheaxisoianothercylindenairinietmeansatthecentralportionoieachofsaid cylinders, fuel inlet means atthe central portionofeachofsaidcylinderaapairotinnerandouteropposedpistonsineachofsaidwlinders. exhaust ports in saidcylindersspaced outwardly tromsaid air inlet and fuel inlet means.connecting means from corresponding pistons ofapairofopposedcylinderstooneotsaidcrankpins, and connecting means fromthe other pisigiiln of the same cylinders to the alined crank- 15. In acompression ignition engine, the combination of a crankshaft. unitgroups o! cylinders including at least one cylinder on each side of saidcrankshaft, said cylinders being disposedwith their longitudinal axescoplanar and with the axes of one row` oiiset with respect to the axesof the other row, air inlet means at the central portions of each ofsaid cylinders, fuel inlet means at the central portions of each of saidcylinders, a pair of inner and outer opposed pistons in each of saidcylinders. said crankshaft having at least three crankpins for each unitgroup of cylinders, two of said crankpins being in aiinement, and meansfor connecting the pistons of the unit groups to said crankshaftincluding connections from corresponding pistons o1 a pair of `opposedcylinders to one of said crankpins, and connections from the otherpistons of the same cylinders to said alined orankpins.

wnrmnwoma.

